Stimulating plant growth



United States Patent Ofiiice 3,235,364 STIMULATING PLANT GROWTH Sanford M. Siegel, White Plains, N.Y., assignor to Union Carbide Corporation, a corporation of New York No Drawing. Filed Nov. 20, 1962, Ser. No. 239,062 15 Claims. (Cl. 71-2.5)

This application is a continuation-in-part of my application Serial No. 154,898, filed November 24, 1961, now abandoned.

This invention relates to treatment of biological systems. More particularly, this invention relates to growth regulation of plants.

A variety of materials have been suggested in the art as growth regulators for plants. These can be generally classified into two groupings (1) growth inhibitors such as weed killers, germination inhibitors, and the like and (2) growth stimulants such as fertilizers and plant hormones. The present invention is directed to particular novel methods for plant growth stimulation.

The presently known plant growth stimulants have had greater or lesser success in practice depending on the particular compound employed and have exhibited considerable variation in their effects on various plants. In addition, in the case of growth stimulants of the fertilizer type, larger and cumbersome amounts have to be applied to the plant before the beneficial effects become apparent.

An object of the present invention is to provide a novel method for stimulating plant growth.

Another object of this invention is to provide a method for promoting the general vegetative development of a plant.

Still another object is to provide a method for promoting the flowering of a plant.

A further object is to provide a method for enhancing the germination of seeds.

These and other objects will become readily apparent upon reference to the ensuing discussion and the appended claims.

The present invention contemplates a method whereby a number of a particular group of organic compounds is applied to the plant or selected portions thereof in an amount sufficient to enhance the rate of development. Organic compounds within the purview of this invention are those which are:

(1) Stable in acidic media;

(2) Characterized by the presence of .a vinyloxy group; and

(3) Selected from the group which includes alkyl vinyl ether, substituted alkyl vinyl ether, aryl vinyl ether, substituted aryl vinyl ether, .and benzofuran.

It is a necessary prerequisite for the present invention that the stimulant compounds are stable in acidic media. This requirement is dictated by the fact that plant systems are acidic in nature, usually having a pH in the range from about 5.5 to about 6.5.

The term vinyloxy group as used herein and in the appended claims characterizes a grouping of two carbon atoms bonded with a double bond, one of said carbon atoms being further bonded with a single bond to an adjacent oxygen atom. The group can also be described as a vinyl or vinylene radical attached to an oxygen atom.

The alkyl vinyl ethers contemplated herein include those containing up to 18 carbon atoms in the alkyl radical. Illustrative alkyl radicals are methyl, ethyl, n-propyl, iso- 3,235,364 Patented Feb. 15, 1966 propyl, n-butyl, sec-butyl, tbutyl, the amyls, the hexyls, the heptyls, the octyls, the dodecyls, the octadecyls, cyclopentyl, cyclohexyl, cycloheptyl, and the like.

For seedling growth, seed germination, and general vegetative development preferred are the aforesaid .alkyl vinyl ethers containing less than eight carbon atoms in the alkyl radical.

The substituted alkyl vinyl ethers contemplated herein include the aralkyl vinyl ethers, the haloalkyl vinyl ethers, the haloaralkyl vinyl ethers, the alkoxyalkyl vinyl ethers, the alkthioalkyl vinyl ethers, the arylthioalkyl vinyl ethers, the d-ialkaminoalkoxyalkyl vinyl ethers, the aryloxyalkyl vinyl ethers, the halogenated aryloxyalkyl vinyl ethers, the hydroxyalkoxyalkyl vinyl ethers, and the like, containing up to eighteen carbon atoms in the substituted alkyl radical.

Particularly preferred for seedling growth, seed germination, and general vegetative development are the haloa'lkyl vinyl ethers containing less than eight carbon atoms in the haloalkyl radical.

For the promotion of flowering and fruiting the alkthioalkyl vinyl ethers, the dialkaminoalkoxy-alkyl vinyl ethers, the halogenated aryloxyalkyl vinyl ethers, and the hyd-roxyalkoxyalkyl vinyl ethers are preferred. Particularly preferred for this purpose are the alkthioalkyl vinyl ethers containing more than seven carbon atoms in the alkthioalkyl radical.

Illustrative aralkyl vinyl ethers are phenylbutyl vinyl ether, phenylpropyl vinyl ether, phenylmethyl vinyl ether, naphthylbutyl vinyl ether, naphthylpropyl vinyl ether, naphthylmethyl vinyl ether, anthrylbutyl vinyl ether, anthrylpropyl vinyl ether, anthrylmethyl vinyl ether, and the like.

Illustrative haloalkyl vinyl ethers are chloromethyl vinyl ether, dichloromet-hyl vinyl ether, bromornethyl vinyl ether, dibromornethyl vinyl ether, tribromomethyl vinyl ether, trichloromethyl vinyl ether, the choloropropyl vinyl ethers, the polychloropropyl vinyl ethers, the bromopropyl vinyl ethers, the polybromopropyl vinyl ethers, the polyohloroethyl vinyl ethers, the polybromoethyl vinyl ethers, the polychlorobutyl vinyl ethers, and the like.

Illustrative haloaralkyl vinyl ethers are chlorophenylbutyl vinyl ether, the polychlorophenylbutyl vinyl ethers, the polybromophenylb-utyl vinyl ethers, the polychlorophenylethyl vinyl ethers, the polychloroanaphthylpropyl vinyl ethers, and the like.

Illustrative alkoxyalkyl vinyl ethers are methoxymethyl vinyl ether, ethoxymethyl vinyl ether, propoxymethyl vinyl ether, methoxyethyl vinyl ether, propoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxypropyl vinyl ether, ethoxypropyl vinyl ether, propoxypropy-l vinyl ether, butoxypropyl vinyl ether, butoxybutyl vinyl ether, and the like.

Illustrative alkthioalkyl vinyl ethers are 2-(S-methyl)- ethyl vinyl ether, 2-(S-ethyl)-ethyl vinyl ether, 2-(S-npropyl)-ethyl vinyl ether, Z-(S-n-butyD-ethyl vinyl ether, 2-(S-n-hexyl)-ethyl vinyl ether, 2-(S-n-octyl)ethyl vinyl ether, 2-(S-n-dodecyl)-ethyl vinyl ether, 'Z-(S-H-hCXEldC- yl)-ethyl vinyl ether, 3-(S-n-octyl)-propyl vinyl ether, 4-(S-n-n0nyl) butyl vinyl ether, and the like. In addition, the alkthioalkyl radical of a vinyl ether can also contain up to 10 atoms as a substituted moiety thereof. Illustrative of these are 2-[S-(2-cyanoethoxy)-ethyl]-ethyl vinyl ether, Z-[S-(2-cyanopropoxy)-ethyl]-ethyl vinyl ether,

' and the like.

Illustrative arylthioalkyl vinyl ethers are 2-(S-phenyl)- ethyl vinyl ether, 3-(S-phenyl)-propyl vinyl ether, 2-(S- phenyl)-propyl vinyl ether, 4-(S-naphthyl)butyl vinyl ether and the like.

Illustrative dialkaminoalkoxylalkyl .vinyl ethers are 2- [2'-(N,N-diethylamino)]-ethoxyethyl vinyl ether, 3-N,N- dimethylaminoethoxypropyl vinyl ether, 2-[2-(N,N-dimethylamino)]propoxybutyl vinyl ether, and the like.

Illustrative aryloxyalkyl vinyl ethers are phenoxymethyl vinyl ether, phenoxyethyl vinyl ether, phenoxy-propyl vinyl ether, phenoxybutyl vinyl ether, phenoxyhexyl vinyl ether, and the like. Also contemplated within this grouping are the alkoxy-substituted aryloxyalkyl vinyl ethers such as 2-(3,5-dimethoxyphenoxy)ethyl vinyl ether, 3- (3,5-diethoxyphenoxy)-propyl vinyl ether, and the like.

Illustrative halogenated aryloxyalkyl vinyl ethers are 2-(2,4-dichlorophenoxy)-ethyl vinyl ether, 2-(2,3,5-trichlorophenoxy)-ethyl vinyl ether, 2-(2,4-dibromophenoxy)-ethyl vinyl ether, 3-(2,3,5-tribromophenoxy) propyl vinyl ether, and the like.

Illustrative hydroxyalkoxyalkyl vinyl ethers are ll-hydroxy-3,6,9-trioxy-undecyl vinyl ether, 5-hydroxy-3-oxyhexyl vinyl ether, 5-hydroxy-3-oxy-4- methyl-hexyl vinyl ether, 7-hydroxy-3-oxy-heptyl vinyl ether, and the like.

The aryl vinyl ethers contemplated herein include phenyl vinyl ether, naphthyl vinyl ether, anthryl vinyl ether, and the like.

The substituted aryl vinyl ethers contemplated herein include the alkaryl vinyl ethers, preferably containing up to six carbon atoms in the alkyl substituents, the haloaryl vinyl ethers, the haloalkaryl vinyl ethers, and the nitroaryl vinyl ethers.

Illustrative alkaryl vinyl ethers are tolyl vinyl ether, xylyl vinyl ether, ethylphenyl vinyl ether, propylphenyl vinyl ether, and the like.

Illustrative haloaryl vinyl ethers are the chlorophenyl vinyl ethers, the bromophenyl vinyl ethers, the polychlorophenyl vinyl ethers, the polybromophenyl vinyl ethers, the polychloronaphthyl vinyl ethers, the polybromonaphthyl vinyl ethers, the chloroanthryl vinyl ethers, the chloroxylyl vinyl ethers, pentachlorophenyl vinyl ether, and the like.

Illustrative haloalkaryl vinyl ethers are the chloromethylphenyl vinyl ethers, the bromomethyl phenyl vinyl ethers, the chloroethylphenyl vinyl ethers, the bromoethylphenyl vinyl ethers, the chlorobutylphenyl vinyl ethers, the chloropropylphenyl vinyl ethers, the chloromethylnaphthyl vinyl ethers, and the like.

Illustrative nitroaryl vinyl ethers are 2,4-dinitrophenyl vinyl ether, the nitrophenyl vinyl ethers, the nitronaphthyl vinyl ethers, the dinitronaphthyl vinyl ethers, and the like.

The benzofurans contemplated herein contain the vinyloxy group in a five-membered heterocyclic ring which can be exemplified by 2-methyl-3-carbethoxy-5- hydroxy benzofuran the structure of which is:

OH 3 000cm,

ated S-hydroxy benzofurans such as 2-methyl-3-carbethoxy-4,6-dibromo-5-hydroxybenzofuran, 2-n propyl-3-carbethoxy-4-bromo-5-hydroxy benzofuran, 2-n-propyl-3-carbethoxy-6#bromo-S-hydroxy-benzofuran, and the like; the salts of benzofuran-derived esters such as sodium salt of 2-methyl-3-carboxy-S-hydroxy-benzofuran ethyl ester, potassium salt of 2-ethyl-3-carboxy-S-hydroxy-benzofuran butyl ester, sodium salt of 2-n-propyl-3-carboxy-5-l1ydroxy-benzofuran ethyl ester, and the like.

The stimulation of growth is conveniently brought about by applying to the seeds, the plant, or particular parts of the plant the aforesaid stimulant compounds directly or along with a carrier such as water, ethanol, or water-ethanol mixtures. The buds of plants, leaves, or similar plant parts may be treated by a direct application of water, water-ethanol, or ethanol solutions in small volumes which would deposit upon evaporation or absorption from about 0.01 to about 3.5 micrograms of the growth-stimulating compounds per 10 to 20 square millimeters of plant surface. The preferred amount in such an instance is from about 0.05 to about 1.5 micrograms per 10 to 20 square millimeters of surface. Optimum results were observed with these amounts upon direct application.

The growth of a plant can also be stimulated by treatment with water, ethanol, or water-ethanol solutions of the stimulant compounds, the Vinyloxy group concentration in the solution being in the range from about 10* to about 10- mole-equivalents per liter of solution. Vinyloxy group concentrations in excess of about l0 moleequivalents per liter of solution were observed to produce no additional beneficial results nor an increase in growth stimulation. Vinyloxy group concentrations below about 10- mole-equivalents per liter of solution were found to be too low to effectively stimulate plant growth.

The growth stimulating compositions of the present invention may be applied directly to the plant by spraying, dipping, etc. The compositions may also be applied to the roots of the plant or to the soil or other growth media in the vicinity of the plant.

Either a single compound or a mixture of compounds containing a Vinyloxy group may be employed for the purpose of growth stimulation.

Moreover, accessory factors such as nutrients (sources for N, P, S, etc.), trace elements, soluble carbohydrates, pesticidal compounds, and the like, may be admixed thereto. These accessory factors, of course, have to be non-toxic to the plant and must be chemically compatible with the stimulant compound containing the vinyloxy group.

The growth-stimulating effect achievable through the teachings of the present invention has been demonstrated with a great variety of plants including cucumber, bean, flax, corn, radish, lettuce, winter rye, alfalfa, tomato, duckweed (Lemna minor), and Coleus. The herein disclosed compounds are particularly effective for increasing germination and seedling growth rates, bud growth, leaf and stem growth, etc., thereby materially enhancing the vigor of plants which include species or varieties of economic value for food, for raw materials, as ornamentals, ground cover, or other uses.

In addition, the foregoing methods are not restricted to higher plants only, but are equally well suited to lower plants such as, for example, the green, fiagellated microorganism Euglena, an alga, which when placed in solutions containing 0.01 to 0.10 micrograms per milliliter of 2-chloroethyl vinyl ether exhibited a two-fold to fourfold increase over the growth rate in standard culture solutions.

Similarly, the beneficial effects of the growth-stimulating methods may be extended to obligate anaerobic and facultative aerobic bacteria, various strains of which are employed in the manufacture of pharmaceutical preparations.

Presently obligate anaerobic bacteria are cultured in sealed, controlled-atmosphere vessels or under high vacuum because of their high oxygen sensitivity. By a treatment of these bacteria with compounds containing a vinyloxy group this oxygen sensitivity may be attenuated and the culturing carried out under less-demanding environmental conditions. By the same token, the growth of facultative aerobic bacteria may be enhanced by the application of the aforesaid growth stimulants.

The foregoing discussion will be augmented and further illustrated by the subsequent experimental examples which demonstrate the effectiveness of the plant-growth stimulation method-s of this invention.

EXAMPLE 1 Common garden bean seedlings were grown for days in ordinary potting soil. At the end of this time plants were separated in groups of 20*25 and the terminal bud was treated directly with 0.01 ml. of distilled water (control) or 0.01 ml. of a solution or suitable stimulating compound in distilled water. Growth was measured regularly, and after 10 days the plants were harvested and their parts weighed and measured.

Representative treatment and harvest data are tabulated below:

Table I INCREASED GROWTH AS A RESULT OF TREATMENT WITH 5-HYD ROXY-BENZOFURANS 2-methyl-3-carboxy-5- hydroxy benzofuran Growth measurement Control Na salt (0.02 Ethyl ester micrograms) (2.0 micrograms) Stem length (cm.) 8.5 10.1 11. 6 Stem weight (gm.) 2. 37 2. 98 3. 50

1st leaf area (emfl)- 32. 4 33.1 71. 4 1st leaf wt. (gm.)- 0.35 0. 43 0.63

The data in Table I illustrate the elfectiveness of both the ethyl ester and the sodium salt of 2-methyl-3-carboxy- S-hydroxy benzofuran ethyl ester in stimulating stem and leaf growth.

Table l INCREASED GROWTH AS A RESULT OF TREATMENT WITH SUBSTITUTED fi-HYDROXY BENZOFURANS 2-methyl-3-carbethoxy fihydroxy benzofuran Growth measurement Control fi-bromo- 4,6-dibrofi-ehloro- (2.5 mieromo-(3.5 (2.0 micrograms) micrograms) grams) Stem length (cm.) 8. 4 9. 4 10. 4 9. 3 Stem weight (g1n.) 2. l1 2. 24 2. 48 2. 34 1st leaf area (em?) 15. 0 21. 2 25. 8 18.0 1st leaf Wt. (gm) 0.13 0.21 0. 25 0.18

Table II shows that substantial increase in stem and growth was achieved after treatment with halogenated S-hydroxy benzofurans as compared to the untreated plants.

EXAMPLE 2 Seeds of winter rye in groups of 33 were germinated in water solutions containing alkyl-carbalkoxy-hydroxyhalo-substituted benzofurans. After hrs. at 25 C., germination percentages were computed and the results 6 expressed as percentage increase attributable to the presence of the stimulant. After an additional 50 hours of incubation, root lengths were measured and the results computed as percentage increase over root length in water alone.

Seeds of Peruvian alfalfa were also used in the manner described for winter rye, except that the final growth measurements were made in terms of weights of Whole seedlings rather than lengths of roots.

In the following table are summarized the results obtained with preferred concentrations of growth stimulants.

Table III GROWTH STIMULATION OF RYE AND ALFALFA WITH HALOGENA'IED BENZOFURANS The data in Table III are indicative of the substantially enhanced germination and growth of rye and alfalfa. In the case of rye, for example, germination has been increased by about percent, and the growth has been increased by about 128 percent by the treatment.

EXAMPLE 3 Ten day old garden bean plants were treated with alkyl vinyl ethers and haloalkyl vinyl ethers by direct application to the terminal bud of 0.01 ml. water solutions of the desired compounds. Growth in length of the bud and bud products was followed daily for an additional 10 days, at which time the plants were harvested and the lengths and weights of plant parts determined. In the following table various results of the treatment employed are summarized.

Table IV GROWTH STIMULATION WITH 2-OHLOROETHYL VINYL ETHER Growth response (in mm. length) at- Total weight of compound applied to bud, 1 day after 2 days after 8 days after micrograms treatment treatment treatment Table IV shows the efiectiveness of growth stimulation by various amounts of 2-chloroethyl vinyl ether applied to the terminal bud of the bean plant in an aqueous solution. In each instance the plants exhibited an increase in growth rate.

7 Table V COMPARISON OF ALKYL VINYL ETI-IERS AND HALO- ALKYL VINYL ETHERS AS GROWTH STIMULAN'IS Growth during 24 Total weight of hrs. as percentage Table V particularly points out the effectiveness of 2- chloroethyl vinyl ether as a growth stimulant. A growth increase of 220 percent during a twenty-four hour period was observed after the application of 0.01 microgram of the compound, and a growth increase of 380 percent was observed during the same time period when 1.00 microgram was applied.

EXAMPLE 4 Seeds of winter rye in groups of 33 were germinated in water or solutions containing substituted alkyl vinyl ethers. After 50 hrs. of incubation, the growth in weight and length of roots was measured. The results of these tests are summarized below:

Table VI GROWTH STIMULATION \VITH SUBSTITUTED ALKYL VINYL ETHERS Growth measurement Concen- Compound tration, Ave. Ave.

moles/l. Number length, Ave. wt.,

of roots/- min. mg.

plant Pentaehlorophenyl vinyl ether 4Xl0- 2. 2 16. 9 189 2,4-dinitrophenyl vinyl ether. 4 l0-- 1. 9 19. 7 258 4-methylphenyl vinyl ether.. lXIO- 1. 9 11.8 189 4-methylphenyl vinyl ether. 1X10' 2. 3 19. 9 274 Control (water only) 1. 5 11.2 141 Table VI illustrates the effectiveness of various representative vinyl ethers in stimulating the germination of winter rye. The average number of roots per plant, their average length, and their average weight increased after the treatment with the vinyl ethers.

EXAMPLE 5 Narcissus bulbs in groups of five were placed in tap water solutions of substituted alkyl vinyl ethers having a vinyloxy group concentration of about l moleequivalents per liter. The number of roots formed after 1, 2, and 4 days was observed and recorded. The experimental results are summarized in Table VII below.

The above data indicate that the substituted alkyl vinyl ethers provide a generally good rooting stimulation. Particular elfeetiveness is exhibited by 2-(S-n-dodecyl)- ethyl vinyl ether and 2-(S-methyl)-ethyl vinyl ether.

8 EXAMPLE 6 Yellow onion bulbs in groups of five Were placed in aqueous solutions of substituted alkyl vinyl ethers having a vinyloxy group concentration of about 10- moleequivalents per liter. The bulbs Were placed so that the entire undersurface of the bulb was immersed in the solution. The number of roots appearing after 3 days and 10 days was observed and recorded. The total fresh weight yield of roots per five bulbs was also determined on the 10th day.

The resulting data demonstrating the stimulating effect are compiled in Table VIII below.

Table VIII STIMULATION OF ROOTING OF ONION BULBS Number of roots/ Root wt., Substituted alkyl 5 bulbs aiter gms./5 bulbs after 10 days 3 days 10 days Untreated (Control) 11 76 0.95 2-(2, 4-diehlorophenoxy)-ethyl vinyl ether 12 153 2. 00 7-hydroxy-3-oxy-heptyl vinyl ether. 7 131 1.82 2-(S-methyl)-ethyl vinyl ether 8 156 2. 78 2(S-n-octyl) ethyl vinyl ether- 10 121 3. 10 2-ehlorocthyl vinyl ether 6 1. 91 1:1 mixture of Z-chloroethyl vinyl ether and 2-(S-methyl)-ethyl vinyl ether 13 111 1. 41 1:1 mixture of 2-ch1oroethyl vinyl ether and 2-(S-n-octyl)-ethyl vinyl ether 94 194 3. 21

The above table also indicates that a synergistic efiect with respect to early rooting is obtained by a mixture of equal parts of 2-chloroethyl vinyl ether and 2-(S-n-octyl)- ethyl vinyl ether in the solution.

EXAMPLE 7 Cuttings of the ornamental plant, Coleus, about 10 cm. long, were immersed in groups of five in an aqueous solution of substituted alkyl vinyl ethers having a vinyloxy group concentration of about 10- mole-equivalents per liter. The number of roots per five cuttings were determined on the 6th and 7th days, and the root lengths on the 10th day. The experimental results are tabulated below in Table IX.

The above table indicates that the formation of roots from stem cuttings can be stimulated by the methods of the present invention.

EXAMPLE 8 In a manner analogous to Example 6, yellow onion bulbs were treated with derivatives of 2-methyl-3-carbethoxy-S-hydroxybenzofuran. The number of roots per five bulbs was determined after four days and eleven days. Root length and root weight per five bulbs was determined after 11 days. The experimental results are tabulated below in Table X.

Table X STIMULATION OF ROOTING OF ONION BULBS WITH SUB STITUTED 2-METHYL-3 CARBETHOXY-5-HYDROXY- 1t) Table XII EFFECTS OF VINYL ETHER DERIVATIVES ON FLOWE RING OF BLACKVALENTINE BEANS BENZOFURANS Percentage of plants Leaf area flowering after 1 week Stimulant compound increase, Roots/5 bulbs Root Root wt./ cmfl, after after length, cm, 5 bulbs, 1 week Buds Open Sum Substituted benzoiuran 11 days gan, 11 flowers ays 4 days 11 days None (Control) 4.2 5 5 10 (a) Aryloxy alkyl vinyl Untreated (Control) 5 101 4. 6 0.96 ethers: 2-methyl-3-carbethoxy-5- 2-(2,4-diehlorophenoxy)- hydroxy-benzofuran 39 174 5. 7 3. D1 ethyl vinyl ether 5. 7 0 15 2-methyl-3-carbethoxy-5- 2-(2,3,5-triehlorophehydroxy-fi-bromonoxy) -ethyl vinyl ether 6. l 29 5 34 benzofuran. 6 144 7.0 1.99 15 2-(3,5-dimethoxyphe- 2-methyl-3-carbethoxy-5- noxy)-ethyl vinyl ether. 1. 5 18 5 23 hydroxy-fi-iodo-benzo- (b) Hydroxyalkoxyalkyl furan 15 67 8. 0 1. 41 vinyl ethers: 2-methyl-3-carbethoxy-5- 11-hydroxy-3,6,9-trioxyrnethoxy-benzofuran. 15 153 10. 4 3. 42 undecyl vinyl ether. 8. 6 12 12 24 2-methyl-3-carbethoxy-5- 5-hy I0xy1-3-0xy-hexyl methoxy-G-brornovinyl ether 9. 5 33 5 38 benzofuran 17 120 6.8 1.44 5-hydroxy-3-oxy4- Inethyl-hexyl vinyl ether- 8. l 31 0 31 7-hydroxy -oxy heptyl vinyl ether 8. 4 42 14 56 (c) S and N containing sub- EXAMPLE 9 stituted alkyl vinyl ethers:

25 2 (S -n-pr0py1)-ethyl 2 vslnyl e tl1 er 4.8 4 34 --D.- '9 Derivatives of 2-methyl-3-carbethoxy-S-hydroxy-benzo- 36 9 4 furans in an aqueous solution were applied directly to the I Y Y Vinyl 3 7 22 4 26 terminal buds of 10-day-old Black Valentine beans. Each 4 fiI i 'ffifi:

amino) ethoxy1-ethyl... termi al bud was treated with 0.01 milliliter of solution 30 vinyl ether 128 15 2O containing either 0.01 to 1.0 mlcrogram of the stimulant 2-[S-(2'-eyanoethoxy)- ethyl -eth lvin l compoupd' etherinfuflj 3.7 22 o 22 The lncrease 1n primary leaf area over initial values and the area of the first trifoliate leaf, the latter being absent at the time of the treatment with the stimulant, 35 f gsgg g z gg aggg 2 $$g g were measured after two weeks. The experimental rep p Sults are tabulated below in Table XI beans. Particularly effective for this purpose appear to be 7-hydroxy-3-oxy-heptyl vinyl ether and 2(S-n-octyl)- ethyl vinyl ether. Table XI 40 EXAMPLE 11 EFFECTS OF SUBSTITUTED 2 METHYL 3 CARBETHOXY 5 Three'weebold Black Valentine bean plants were 4 t 4 a o HYDROXY BENZOFURANS ON BEAN LEAF EXPANSION treated m groups of 20 -80 with substituted alkyl vlnyl ethers. About 0.01 milliliter of an aqueous solution containing about 10- mole-equivalents of vinyloxy groups Amt ff zggfig per liter was applied directly to the bud of the plant. Substituted benzofuran applied The plants were then left undisturbed at flowering but were "23 Primary M harvested for the crop of young pods after three weeks. leaves foliate leaf The observed results are compiled in Table XIII below.

T abl XIII Untreated (Control) 8.4 4.5 e 2-methyl-3-carbethoxy-4-methoxy- STIMULATION 0F FRUITING IN BLACK VALENTINE fi-bronlo-benzofuran 1. 0 20. 1 18. 7 BEANS 2-methyl-3-carbethoxy-4,6-bromo- 5-methoxy-benzofuran 0. 01 18. 7 6. 3 2-methyl-3-carbethoxy-5-methoxy- Fruiting after 3 weeks 6-i0do-benzofuran. O. 01 13.8 3. 6 2-methyl-3-carbethoxyhloror benzofuran 0. 01 20. 1 11.1 50 Fruiting stimulant Fresh wt. of Fresh wt., Length, 2-1nethyl-3-carbethox pods, gm./20 mgrnJpod nmL/pod benzofuran l. 0 2. 64 18. 9 plants No2ne pgrlltrobfi 2.63 90 21 The foregoing results indicate that primary leaf growth 'g g, f i 429 180 32 was stimulated by every compound tested and that trlfi -g g p 3 42 210 37 foliate leaf growth was stimulated by all but 2-methyl-3- 5-hydroxy-4-Inethy13- hexyl vinyl ether 4. 94 300 43 carbethoxy 5 methoxy 6 lodo benzofuran. msvmpwpynethyl vinyl ether s. 92 320 40 2-(S-n-dodeoyl)ethyl vinyl EXAMPLE 10 ether 4. 26 310 41 Three-week-old Black Valentine bean plants were ;g ibove g g a s treated in groups of 20-30 with substituted alkyl vinyl p yl ave age yle 6 ance y the methods of the present invention. Particularly etethers. About 0.01 milliliter of an aqueous solution con- 7 2 0 fectlve fruiting stimulant in this respect appears to be 2- talnmg about 10 mole-equivalents of vlnyloxy groups (s n propyl) ethyl vinyl ether per liter was applied directly to the bud of the plant. The number of flower buds and flowers were determined and EXAMPLE 12 growth measurements taken after one Week- The P Bulbs of the ornamental, narcissus, were immersed in mental results are summarized in Table XII below. aqueous growth stimulant solutions having a vinyloxy group concentration of about 10- mole-equivalents per liter. The bulbs were immersed so that the entire bottom surface was contacted by the solution and were maintained under room lighting conditions and at about 70 F.

Experimental observations included the noting of the number of roots after 2 days and 4 days, the length of the flower stalk after 7 days, and the number of bulbs flowering after 10 days. The data are compiled in Table XIV below.

Table XIV STIMULATION OF NARCISSUS BULB DEVELOPMENT Roots/5 bulbs atter- Flower stalk, Bulbs flower- Stimulant compound cm. after 7 ing per 5,

days alter 10 days 2 days 4 days Untreated (Control) 0 52 4. 2 2-[N-methyl-N-(2-hydroxyethyl)]-ethyl vinyl ether 23 143 6. 4 2-(S-methyl)-ethyl vinyl ether 11 161 6. 4 Z-(S-noctyDcthyl vinyl ether 29 102 7. 7 2 Z-(S-n-dodecyD-ethyl vinyl ether 19 178 8. 6 1

The above data indicate that both the root and floral structure development can be enhanced through the use of the methods of the present invention. 7 Particularly suitable for this purpose are the substituted alkyl vinyl ethers.

EXAMPLE 13 One-month-old Manalucie tomato plants were sprayed with a 10 M aqueous solution of selected growth stimulants. The flowering and fruiting of thesprayed plants one week after spraying was observed. The results are compiled in Table XV below.

Table X SIMULATION OF FLOWERING AND FRUITING IN TOMATO PLANTS The foregoing table indicates that the substituted alkyl vinyl ethers generally promote the rate of flower bud development into flowers and fruit in tomato plants. Particularly effective for bud production in number is 2-(S- n-octyl)-ethyl vinyl ether.

EXAMPLE 14 The terminal bud of Coleus, an ornamental, was treated with 10- moles of a substituted alkyl vinyl ether applied directly to the bud. Two weeks after the treatment the plants were examined for the presence of a flower spike. The experimental results are compiled below in Table XVI.

None (Control) 5-hydroxy-3-oxy-hexyl vinyl ether. 7-hydroxy-3-oxy-heptyl vinyl ether 2-[2-(N, N -diethylamino-) ethoxy1- hylv y ether. 2-(S-n-propyl)-ethyl vinyl ether..- 2-(S-n-octyD-ethyl vinyl ether EJINN is ue The above data indicate that the substituted alkyl vinyl ethers are effective flowering stimulants for Coleus. Optimum results were obtained with 2-(S-noctyl)-ethyl vinyl ether and 5-hydroxy-3-oxy-hexyl vinyl ether.

The plant growth stimulating methods discussed herein with specific reference to particular vinyloxy-group-containing compounds may also be practiced with analogous compounds which comprise a vinyl or vinylene group attached to an oxygen analogue such as sulfur and nitrogen.

The foregoing discussion and the accompanying examples are intended to be illustrative of the present invention but are not to be construed as limitations thereof. Other embodiments within the spirit and scope of the present invention will readily present themselves to one skilled in the art.

I claim:

1. Method for stimulating growth of a plant which comprises applying thereto in an amount sufficient to enhance the rate of development of at least a portion of said plant an organic compound which is:

(l) stable in acidic media;

(2) characterized by the presence of a vinyloxy group;

and

(3) contains up to 18 carbon atoms and is selected from the group consisting of an alkyl vinyl ether, a substituted alkyl vinyl ether, an aryl vinyl ether, a substituted aryl vinyl ether, and a benzofuran;

said substituted alkyl vinyl ether being a member of the group consisting of aralkyl vinyl ether, haloalkyl vinyl ether, haloaralkyl vinyl ether, alkoxyalkyl vinyl ether, alkthioalkyl vinyl ether, arylthioalkyl vinyl ether, dialkaminoalkoxyalkyl vinyl ether, and hydroxyalkoxyalkyl vinyl ether; and

said substituted aryl vinyl ether being a member of the group consisting of alkaryl vinyl ether, haloaryl vinyl ether, haloalkaryl vinyl ether, and nitroaryl vinyl ether.

2. Method for stimulating growth of a plant which comprises applying thereto in an amount sufficient to enhance the development of at least a portion of said plant an aqueous solution of an alkyl vinyl ether having less than eight carbon atoms in the alkyl radical; said alkyl vinyl ether being present in said solution in an amount suificient to provide a vinyloxy group concentration in the range from about 10- to about 10'- mole-equivalents per liter of solution.

3. The method in accordance with claim 2 wherein the alkyl vinyl ether is ethyl vinyl ether.

4. The method in accordance with claim 2 wherein the alkyl vinyl ether is n-butyl vinyl ether.

5. Method for stimulating growth of a plant which comprises applying thereto in an amount sufficient to enhance the development of at least a portion of said plant an aqueous solution of a haloalkyl vinyl ether having less than eight carbon atoms in the haloalkyl radical; said haloalkyl vinyl ether being present in said solution in an amount sufficient to provide a vinyloxy group concentration in the range from about 10- to about 10- moleequivalents per liter of solution.

6. The method in accordance with claim wherein the haloalkyl vinyl ether is 2-chloroethyl vinyl ether.

7. The method in accordance with claim 5 wherein the haloalkyl vinyl ether is Z-bmmoethyl vinyl ether.

8. Method for promoting flowering of a plant which comprises applying thereto in an amount suflicient to enhance the development of flowers an aqueous solution of an alkthioalkyl vinyl ether having up to 18 carbon atoms in the alkthioalkyl radical; said alkthioalkyl vinyl other being present in said solution in an amount sufiicient to provide a vinyloxy group concentration in the range from about to about 10- mole-equivalents per liter of solution.

9. The method in accordance with claim 8 wherein the alkthioalkyl vinyl ether is 2-(S-n-octyl)et-hyl vinyl ether.

10. Method for promoting flowering of a plant which comprises applying thereto in an amount suflicient to enhance the development of flowers an aqueous solution of a dialkaminoalkoxyalkyl vinyl ether having up to 18 carbon atoms in the dialkaminoalk-oxyalkyl radical; said dialkaminoalkoxyalkyl vinyl ether being present in said solution in an amount suflicient to provide a vinyloxy group concentration in the range from about 10 to about 10* mole-equivalents per liter of solution.

11. The method in accordance with claim 10 wherein the dialkaminoalkoxyalkyl vinyl ether is 2-[2'-(-N,N-di ethylamino)ethoxy]ethyl vinyl ether.

12. Method for promoting flowering of a plant which comprises applying thereto in an amount suflicient to enhance the development of flowers an aqueous solution of a hydroxyalkoxyalkyl vinyl ether having up to 18 carbon atoms in the hydroxyalkoxyalkyl radical; said hydroxyalkoxyalkyl vinyl ether being present in said solution in an amount sufficient to provide a vinyloxy group concentration in the range from about 10- to about 10- moleeqnivalents per liter of solution.

13. The method in accordance with claim 12 wherein the hydroxyalkoxyalkyl vinyl ether is 7-hydroxy-3-oxyheptyl vinyl ether.

14. Method for promoting germination of a seed which comprises applying thereto in an amount sufficient to enhance said germination an aqueous solution of an alkyl vinyl ether having less than eight carbon atoms in the alkyl radical; said alkyl vinyl ether being present in said solution in an amount suflicient to provide a vinyloxy group concentration in the range from about 10- to about 10' mole-equivalents per liter of solution.

15. Method for promoting germination of a seed which comprises applying thereto in an amount suflicient to enhance said germination an aqueous solution of an alkylcarbalkoxy-hydroxy-halo-substituted benzofuran having up to 18 carbon atoms; said benzofuran being present in said solution in an amount suflicient to provide a vinyloxy group concentration in the range from about 10' to about 10- mole-equivalents per liter of solution.

References Cited by the Examiner UNITED STATES PATENTS 2,603,560 7/1952 Stewart 71-2.3 2,694,696 11/1954 Melamed 71-2.3 3,131,166 4/1964 Harris et a1. 412.3 X

LEWIS GOTIS, Primary Examiner.

JULIAN S. LEVI'I'I, Examiner. 

1. METHOD FOR STIMULATING GROWTH OF A PLANT WHICH COMPRISES APPLYING THERETO IN AN AMOUNT SUFFICIENT TO ENHANCE THE RATE OF DEVELOPMENT OF AT LEAST A PORTION OF SAID PLANT AN ORGANIC COMPOUND WHICH IS: (1) STABLE INACIDIC MEDIA; (2) CHARACTERIZED BY THE PRESENCE OF A VINYLOXY GROUP; AND (3) CONTAINS UP TO 18 CARBON ATOMS AND IS SELECTED FROM THE GROUP CONSISTING OF AN ALKYL VINYL ETHER, A SUBSTITUTED ALKYL VINYL ETHER, AN ARYL VINYL ETHER, A SUBSTITUTED ARYL VINYL ETHER, AND A BENZOFURAN; SAID SUBSTITUTED ALKYL VINYL ETHER BEING A MEMBER OF THE GROUP CONSISTING OF ARALKYL VINYL ETHER, HALOALKYL VINYL ETHER, HALOARALKYL, VINYL ETHER, ALKOXYALKYL VINYL ETHER, ALKTHIOALKYL VINYL ETHER, ARYLTHIOALKYL VINYL ETHER, DIALKAMINOALKOXYALKYL VINYL ETHER, AND HYDROXYALKOXYALKYL VINYL ETHER; AND SAID SUBSTITUTED ARYL VINYL ETHER BEING A MEMBER OF THE GROUP CONSISTING OF ALKARYL VINYL ETHER, HALOARYL VINYL ETHER, HALOALKARYL VINYL ETHER, AND NITROARYL VINYL ETHER. 